In general, a vehicle includes a latch apparatus that retains a door at a full close position. A door handle arranged on a door connects to the latch apparatus. In order to open the door that is at the full close position, the door handle is held and pulled strongly to release the door from being retained at the full close position by the latch apparatus. More specifically, a particularly large operational force is required in the beginning at a time of opening the door.
A vehicle including a door actuating apparatus for automatically opening and closing a door that is rotatably supported by a vehicle body is disclosed in JP2005-232752A, hereinafter referred to as Reference 1. The door actuating apparatus disclosed in Reference 1 includes a rod formed in an elongated form and a driving mechanism driving the rod. One end of the rod is retained by the vehicle body to be rotatable. The other end of the rod is retained by a retaining member arranged inside the door such that the rod is configured to advance and retract relative to the door. The driving mechanism is mounted inside the door. The driving mechanism includes an electric motor and a power transmission mechanism. The power transmission mechanism converts rotational movement of the electric motor into linear movement and transmits power from the electric motor to the rod. The power transmission mechanism includes, for example, a worm gear mounted on a driving shaft of the electric motor, a worm wheel meshing with the worm gear, a reducer formed by a multiple number of gears rotating in accordance with rotation of the worm wheel, and a rack gear meshing with one of a multiple number of gears forming the reducer. The other end of the rod is mounted on the rack gear. In addition, an electromagnetic clutch is arranged between the worm wheel and the reducer. A switch for operating the door to open and to close is provided on a portable device or a on a vehicle. The electric motor is actuated when the switch is operated. When the electric motor is actuated in a state where the electromagnetic clutch is connected, driving power of the electric motor is transmitted to the rod. As a result, the door automatically rotates between a full close position and a full open position. In a state where the electromagnetic clutch is connected and the electric motor is not actuated, the door does not move. More specifically, the door is restrained from rotating from a stopped position because the worm gear restrains rotation of the worm wheel. Accordingly, a user may not be able to manually open and close the door. In a state where the electromagnetic clutch is disconnected, rotations of the gears forming the reducer are not transmitted to the worm wheel so that the user may manually open and close the door. Accordingly, the door actuating apparatus according to Reference 1 may open and close the door without difficulty by a simple operation of an operation button. In addition, the door may be manually opened and closed by setting the electromagnetic clutch in a disconnected state.
Nevertheless, the door actuating apparatus according to Reference 1 requires actuation of the electric motor in addition to actuation of the electromagnetic clutch. Accordingly, a drive circuit, for example, a power source circuit, for actuating each of the electric motor and the electromagnetic clutch becomes large in size. In addition, each of the electromagnetic clutch and the electric motor requires separate control. Computer hardware and software configurations of a control apparatus become complex in order to control each of the electromagnetic clutch and the electric motor. Accordingly, a large number of components may be required and cost may increase.
A need thus exists for a door actuating apparatus, which is not susceptible to the drawbacks mentioned above.